The invention relates to clamping apparatus. While particularly adapted to clamping together the stakes and crossmembers of a trellis apparatus used by commercial farmers, it will be understood that the invention also has application to other structures.
Commercial grape farmers typically use a trellis structure which includes vertical stakes disposed in rows. Each stake has carried thereon a crossarm. The size of the stake will vary although there are three common sizes. The common sizes are 13/4", 2", and 21/4". Parallel wires extend between adjacent crossbars. Usually there are four parallel wires which are pulled tight to support grape vines which hang downwardly from the wires. The vines wind around the wires and are harvested ordinarily by mechanical apparatus. The mechanical apparatus typically straddles the wires on which the vines are disposed and the grapes are shaken or knocked off as opposed to being picked. The apparatus normally includes receptacles for receiving the grapes.
The crossarms are typically metal and the stakes or uprights are usually wood. The crossarms typically are provided with slots or metal tabs which serve to retain the wires.
A difficulty in mounting the crossarms to the stakes relates to the need for apparatus which will quickly secure the crossarm to the stake and which will be sufficiently secure so that the crossarm will not be vulnerable to loosening despite the action of the mechanical harvesting apparatus which shakes or knocks off the grapes.
It is an object of the invention to provide apparatus which is easy and fast to install.
It is another object of the invention to provide apparatus which is adjustable to accommodate stakes of varying sizes.
Another object of the invention is to provide apparatus which is simple and inexpensive to manufacture.